Tweening FlxGroups

I created a text box for dialogue in my game, using a FlxGroup with the background sprite, and FlxText elements added to it. I'd like to fade the box and text out after a few second, but when I was looking at FlxTween I realized it had to be an object, and did not see any apparent way to do this for FlxGroup objects. I was looking at the FlxGroup foreach functions, and initially thought I might be able to perform a tween on each member, but it seems this would do that one by one, rather than all at once. I was wondering how I might go about doing this.